I believe there’s a standard tab character between the name and the phone number, but in MS Word the ‘tab stop’ was set up on the ruler to be right aligned. But when it’s imported to InDesign, it regards it as a standard tab character and treats at such. So the solution would be to use GREP to find any tab character that precedes a phone number, and replace it with a right-aligned tab.
P.S. I don’t know what the format of your telephone numbers are and therefore the GREP expression cannot be too specific, so I assume that you don’t have any other lines that contains a tab with a digit following it. If you do, then this will change that tabs as well, which you probably do not want. Unless of course you tell me the format of your telephone numbers, and I can write a more specific expression.
Following are the GREP FInd/Change settings:
Find What: (?=\d)
Change To: ~y